From: Will Deacon <will.deacon@arm.com>
To: Rob Herring <robherring2@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>,
Nicolas Pitre <nico@fluxnic.net>, Greg KH <greg@kroah.com>,
"ming.lei@canonical.com" <ming.lei@canonical.com>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"stern@rowland.harvard.edu" <stern@rowland.harvard.edu>,
Mark Salter <msalter@redhat.com>,
Chen Peter-B29397 <B29397@freescale.com>,
"linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] usb: ehci: make HC see up-to-date qh/qtd descriptor ASAP
Date: Wed, 31 Aug 2011 20:35:25 +0100 [thread overview]
Message-ID: <20110831193525.GA27476@e102144-lin.cambridge.arm.com> (raw)
In-Reply-To: <4E5E7B35.9080008@gmail.com>
On Wed, Aug 31, 2011 at 07:19:33PM +0100, Rob Herring wrote:
> On 08/31/2011 12:51 PM, Will Deacon wrote:
> > Another thing that Marc and I tried on OMAP4 was not bringing up the secondary
> > CPU during boot (by commenting out most of smp_init). In this case, I/O
> > performance was good until we tried to online the secondary CPU. The online
> > failed but after that the I/O performance was certainly degraded.
> >
>
> Was the SCU enabled at that point? One diff between nosmp boot and
> offlining the 2nd core would be that the SCU remains enabled in the
> latter case. I think the SCU does not get enabled for nosmp.
Our rudimentary test (printing out the SCU control register during boot)
showed that it *was* enabled for nosmp. I think this is due to the secure
world having to do that on OMAP so it's probably not true for other
platforms.
Will
WARNING: multiple messages have this Message-ID (diff)
From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] usb: ehci: make HC see up-to-date qh/qtd descriptor ASAP
Date: Wed, 31 Aug 2011 20:35:25 +0100 [thread overview]
Message-ID: <20110831193525.GA27476@e102144-lin.cambridge.arm.com> (raw)
In-Reply-To: <4E5E7B35.9080008@gmail.com>
On Wed, Aug 31, 2011 at 07:19:33PM +0100, Rob Herring wrote:
> On 08/31/2011 12:51 PM, Will Deacon wrote:
> > Another thing that Marc and I tried on OMAP4 was not bringing up the secondary
> > CPU during boot (by commenting out most of smp_init). In this case, I/O
> > performance was good until we tried to online the secondary CPU. The online
> > failed but after that the I/O performance was certainly degraded.
> >
>
> Was the SCU enabled at that point? One diff between nosmp boot and
> offlining the 2nd core would be that the SCU remains enabled in the
> latter case. I think the SCU does not get enabled for nosmp.
Our rudimentary test (printing out the SCU control register during boot)
showed that it *was* enabled for nosmp. I think this is due to the secure
world having to do that on OMAP so it's probably not true for other
platforms.
Will
next prev parent reply other threads:[~2011-08-31 19:35 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-30 16:03 [PATCH] usb: ehci: make HC see up-to-date qh/qtd descriptor ASAP ming.lei-Z7WLFzj8eWMS+FvcfC7Uqw
2011-08-30 16:03 ` ming.lei at canonical.com
2011-08-30 16:15 ` Alan Stern
2011-08-30 16:15 ` Alan Stern
2011-08-30 16:38 ` Mark Salter
2011-08-30 16:38 ` Mark Salter
2011-08-30 17:15 ` Alan Stern
2011-08-30 17:15 ` Alan Stern
2011-08-30 18:45 ` Mark Salter
2011-08-30 18:45 ` Mark Salter
2011-08-30 17:26 ` Will Deacon
2011-08-30 17:26 ` Will Deacon
[not found] ` <20110830172642.GE3464-SGELLbQ0bobZROr8t4l/smS4ubULX0JqMm0uRHvK7Nw@public.gmane.org>
2011-08-30 17:48 ` Greg KH
2011-08-30 17:48 ` Greg KH
2011-08-30 17:54 ` Will Deacon
2011-08-30 17:54 ` Will Deacon
[not found] ` <20110830175432.GG3464-SGELLbQ0bobZROr8t4l/smS4ubULX0JqMm0uRHvK7Nw@public.gmane.org>
2011-08-31 0:23 ` Chen Peter-B29397
2011-08-31 0:23 ` Chen Peter-B29397
2011-08-31 8:49 ` Will Deacon
2011-08-31 8:49 ` Will Deacon
2011-08-31 12:33 ` Chen Peter-B29397
2011-08-31 12:33 ` Chen Peter-B29397
2011-08-31 13:43 ` Mark Salter
2011-08-31 13:43 ` Mark Salter
2011-08-31 15:21 ` Will Deacon
2011-08-31 15:21 ` Will Deacon
2011-08-31 15:27 ` Mark Salter
2011-08-31 15:27 ` Mark Salter
2011-08-31 16:12 ` Marc Zyngier
2011-08-31 16:12 ` Marc Zyngier
2011-08-31 16:55 ` Marc Dietrich
2011-08-31 16:55 ` Marc Dietrich
2011-09-01 10:34 ` Marc Zyngier
2011-09-01 10:34 ` Marc Zyngier
[not found] ` <4E5F5FA9.3010305-5wv7dgnIgG8@public.gmane.org>
2011-09-01 11:13 ` Marc Dietich
2011-09-01 11:13 ` Marc Dietich
2011-09-01 19:08 ` Stephen Warren
2011-09-01 19:08 ` Stephen Warren
2011-09-02 9:50 ` Marc Zyngier
2011-09-02 9:50 ` Marc Zyngier
2011-09-02 17:07 ` Stephen Warren
2011-09-02 17:07 ` Stephen Warren
[not found] ` <74CDBE0F657A3D45AFBB94109FB122FF04B327A383-C7FfzLzN0UxDw2glCA4ptUEOCMrvLtNR@public.gmane.org>
2011-09-02 11:13 ` Marc Dietich
2011-09-02 11:13 ` Marc Dietich
2011-08-31 17:46 ` Nicolas Pitre
2011-08-31 17:46 ` Nicolas Pitre
2011-08-31 17:51 ` Will Deacon
2011-08-31 17:51 ` Will Deacon
[not found] ` <20110831175147.GI8777-SGELLbQ0bobZROr8t4l/smS4ubULX0JqMm0uRHvK7Nw@public.gmane.org>
2011-08-31 18:19 ` Rob Herring
2011-08-31 18:19 ` Rob Herring
2011-08-31 18:35 ` Mark Salter
2011-08-31 18:35 ` Mark Salter
2011-08-31 18:49 ` Rob Herring
2011-08-31 18:49 ` Rob Herring
[not found] ` <4E5E8230.9060307-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2011-08-31 18:58 ` Mark Salter
2011-08-31 18:58 ` Mark Salter
2011-08-31 19:35 ` Will Deacon [this message]
2011-08-31 19:35 ` Will Deacon
2011-09-08 22:41 ` Mark Salter
2011-09-08 22:41 ` Mark Salter
[not found] ` <1315521779.2313.29.camel-PDpCo7skNiwAicBL8TP8PQ@public.gmane.org>
2011-10-31 6:49 ` Pandita, Vikram
2011-10-31 6:49 ` Pandita, Vikram
2011-08-31 0:56 ` Ming Lei
2011-08-31 0:56 ` Ming Lei
2011-09-01 23:16 ` Grant Grundler
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